1. Field of the Invention
This application relates to an object sound period detection apparatus, an object sound period detection apparatus, a noise estimating apparatus and SNR (Signal to Noise ratio) estimation apparatus.
2. Description of Related Art
A conventional object sound period detection apparatus detects an object sound period such as a speech period in an input signal based on a predetermined threshold. Specifically, if an estimated SNR of the input signal is bigger than the predetermined threshold, the conventional object sound period detection apparatus determines that the input signal is a signal of the speech period (see, for example, Non-patent literature, R. Martin, “An efficient algorithm to estimate the instantaneous SNR of speech signals,” in Proc. EUROSPEECH 1993, pp 1093-1096, 1993).
However, it is desired that the precision of object sound period detection improves more.